Scanning speed control device and method

ABSTRACT

A control device and a method for controlling scanning speed of a scanner. The control device includes a decision device and a driving device. The decision device further includes an image buffer, an up-down counter and a comparator. The decision device receives the input image data and utilizes the up-down counter to compute data access volume inside the image buffer. The comparator decides whether to increase or decrease the scanning speed according to the data access volume and also outputs decision data to the driving device.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a scanning control device and ascanning speed control method. More particularly, the present inventionrelates to a scanning speed control device and a scanning speed controlmethod.

2. Description of Related Art

Due to rapid progress in office equipment technologies, various types ofcomplementary systems including the auto-document feeder (ADF) aredeveloped. An auto-document feeder (ADF) can be applied to differenttypes of machines such as a printer, a photocopier or a scanner so thatpaper is fed into the machine without manual labor. If the auto-feedercontains papers, the processor unit (a processor or an applicationspecific integrated circuit) inside the machine detects the presence ofpapers through sensors. When a machine having an auto-feeder needspaper, paper is automatically fed into the machine according tocontrolling signal produced by the processor unit. Thus, auto-feederfacilitates the operation of most machines. However, when an auto-feederis applied to a scanner, due to special design condition of themechanism used by the auto-feeder, forward and backward scanning by thescanner is restricted.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide scanningspeed control device that controls the running speed of a motor andreduces probability of moving forward and backward without sacrificingscanning speed. An up-down counter is used to record current transactionvolume of an image buffer so that an appropriate scanning speed can beset to optimize the scanning speed.

To achieve these and other advantages and in accordance with the purposeof the invention as embodied and broadly described herein, the inventionprovides a control device for controlling the scanning speed of ascanner. The control device includes a decision device, a driving deviceand an input/output interface. The decision device receives input imagedata and transmits decision data and output image data. The drivingdevice receives decision data and the input/output interface receivesthe output image data.

The decision device of this invention controls the scanning speed. Thedecision device includes an image buffer, an up-down counter and acomparator. The image buffer receives the input image data, stores thedata temporarily in a register and finally transmits output image data.The up-down counter computes and records amount of data accessed throughthe image buffer, and then outputs count data. The comparator receivesthe count data and decides to increase or decrease current scanningspeed according to the count data and finally outputs the decision data.

This invention also provides a method of controlling scanning speed of ascanner. First, count data and the largest data access volume areprovided. According to a ratio between the count data and the largestdata access volume, the scanning speed of the scanner is set.

In brief, utilizing the data access volume of the image buffer and thecount data to the comparator, the comparator can determine if a paper isin the initial feed state, the intermediate state or theterminal-scanning state so that a different scanning speed appropriateto the particular state is employed.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings,

FIG. 1 is a schematic block diagram showing a scanning speed controldevice according to one preferred embodiment of this invention; and

FIG. 2 is a flow diagram showing the method of controlling the scanningspeed of a scanner according to one preferred embodiment of thisinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

FIG. 1 is a schematic block diagram showing a scanning speed controldevice according to one preferred embodiment of this invention. As shownin FIG. 1, the control device includes an input device 10, a decisiondevice 12, a driving device 14 and an input/output interface 16. Theinput device 10 further includes an optical sensor 100, ananalogue/digital converter 102 and an image processor 104. The decisiondevice 12 further includes an image buffer 120, a counter 122 and acomparator 124. The driving device 14 further includes a motorcontroller 140 and an electric motor 142.

The analogue/digital converter 102 couples with the optical sensor 100.The image processor 104 couples with the analogue/digital converter 102and the image buffer 120. The image buffer 120 couples with theinput/output interface 16. The up-down counter 122 couples with theinput terminal of the image buffer 120 and the output terminal of theimage buffer 120. The comparator 124 couples with the up-down counter122 and the motor controller 140. The motor controller 140 couples withthe electric motor 142.

To conduct a scanning operation, the optical sensor 100 utilizes acharge coupled device (CCD) to detect any external signal. Each CCD cellconverts the intensity of light into an electrical current. The electriccurrent transforms into signal charges and finally appears as a voltagepotential. Eventually an analogue signal is produced. The analoguesignal is output from the optical sensor 100 to the analogue/digitalconverter 102. As soon as the analogue/digital converter 102 receivesthe analogue signal, the analogue signal is converted to a digitalsignal and the digital signal is immediately transferred to the imageprocessor 104. Inside the image processor 104, the digital signal isprocessed and converted into input image data. The input image data istransferred to the image buffer 120 and the up-down counter 122.

When the image buffer 120 receives the input image data, the input imagedata is temporarily stored. After complete processing of the input imagedata inside the image buffer 120, the input image data is converted tooutput image data and then the output image data is transferred to theinput/output interface 16 and the up-down counter 122.

When the image processor 104 outputs input image data to the imagebuffer 120, the up-down counter 122 enables its up-counting function sothat one is added to the value inside the counter 122. Similarly, whenthe up-down counter senses the transfer of an output image data to theinput/output interface 16, the up-down counter 122 enable itsdown-counting function so that one is deducted from the value inside thecounter 122. After updating the count data within the up-down counter122, the count data is transmitted to the comparator 124. In thisembodiment, only one type of counting method is illustrated. Obviously,other types of counting methods are available for selection. The up-downcounter 122 is a device for computing and recording data access volumeof the image buffer 120 and outputting count data to the comparator 124.

The comparator 124 decides to increase or slow down the scanning speedaccording to the received count data and outputs decision data to themotor controller 140. The motor controller 140 controls the runningspeed of the electric motor 142 according to the decision data. Forexample, if the amount of count data in the image buffer 120 drops, thisindicates the scanning is near completion. The comparator 124 informsthe motor controller 140, via the decision data, to slow down theelectric motor 142.

The comparator in FIG. 1 indicates the need for a method for decidingwhether to increase or decrease the scanning speed of a scanner. Thefollowing is an illustration of such a decision method.

FIG. 2 is a flow diagram showing the method of controlling the scanningspeed of a scanner according to one preferred embodiment of thisinvention. First, count data and the largest data access volume isprovided. According to a ratio of the count data over the largest dataaccess volume, a scanning speed is set. Thereafter, as shown in FIG. 2,step 20 is executed so that whether the count data is greater than % ofthe largest data access volume is checked. If the count data is greaterthan ¾ of the largest data access volume, step 26 is executed so thatthe scanning speed is adjusted to full speed. On the other hand, if thecount data is smaller than ¾ of the largest data access volume, step 22is executed to determine if the count data is greater or smaller than ½of the largest data access volume. If the count data is greater than ½of the largest data access-volume, step 28 is executed such that thescanning speed is set to ¾ of the full speed. On the other hand, if thecount data is smaller than ½ of the largest data access volume, step 24is executed to determine if the count data is greater or smaller than ¼of the largest data access volume. If the count data is greater than ¼of the largest data access volume, step 30 is executed such that thescanning speed is set to ½ of the full speed. On the other hand, if thecount data is smaller than ¼ of the largest data access volume, step 32is executed such that the scanning speed is set to ¼ of the full speed.In practice, anybody familiar with such technique is free to decide therelationship between the scanning speed of the scanner and the datacount/largest data access volume ratio.

In conclusion, one major advantage of this invention is the variation ofscanning speed according to the stored data inside the image buffer sothat an optimal scanning speed can be maintained even ifforward/backward scanning is restricted.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1-11. (canceled)
 12. An apparatus, comprising: a decision device capableof receiving input image data from an input device and outputtingdecision data based at least in part on count data or data accessvolume, or combinations thereof; and a driving device coupled to thedecision device, said driving device capable of receiving the decisiondata and capable of adjusting scanning speed according to the decisiondata.
 13. The apparatus of claim 12, wherein the decision devicecomprises: an up-down counter coupled to an input terminal of an imagebuffer and an output terminal of the image buffer, said up-down countercapable of counting data access volume inside the image buffer andoutputting count data.
 14. The apparatus of claim 12, wherein thedecision device comprises: an up-down counter coupled to an inputterminal of an image buffer and an output terminal of the image buffer,said up-down counter capable of counting data access volume inside theimage buffer and outputting count data; and wherein the up-down counteris capable of updating said count data if the up-down counter detectstransfer of input image data into the image buffer, and wherein theup-down counter is capable updating said count data if the counterdetects transfer of output image data to the input/output interface. 15.The apparatus of claim 12, wherein the decision device comprises: animage buffer coupled to an output terminal of the input device, saidimage buffer capable of receiving the input image data; an up-downcounter coupled to the image buffer; said up-down counter capable ofcounting data access volume inside the image buffer and outputting countdata; and a comparator coupled to the up-down counter, said comparatorcapable of receiving the count data, and capable of deciding whether toadjust the scanning speed according to the count data and outputting thedecision data.
 16. The apparatus of claim 12, further comprising aninput device coupled to said decision device, said input devicecomprising: an optical sensor capable of receiving an external signaland outputting an analog signal; an analog/digital converter coupled tothe optical sensor, said analog/digital converter capable of receivingthe analog signal and converting the analog signal into a digitalsignal; and an image processor coupled to the analog/digital converterand the decision device, said image processor capable of receiving thedigital signal and converting the digital signal into the input imagedata.
 17. The apparatus of claim 12, wherein the driving device furthercomprises: an electric motor; and a motor controller coupled to theelectric motor and the decision device, said motor controller capable ofreceiving the decision data and controlling the running speed of theelectric motor according to the decision data.
 18. A method, comprising:receiving input image data from an input device via a decision device;outputting decision data based at least in part on count data or dataaccess volume, or combinations thereof via said decision device; andreceiving the decision data via a driving device coupled to the decisiondevice; and adjusting scanning speed according to the decision data viasaid driving device.
 19. The method of claim 18, further comprising:counting data access volume inside an image buffer and outputting countdata via an up-down counter coupled to an input terminal of the imagebuffer and an output terminal of the image buffer.
 20. The method ofclaim 18, further comprising: updating said count data if transfer ofinput image data into an image buffer is detected or updating said countdata if transfer of output image data to the input/output interface isdetected, or combinations thereof.
 21. An apparatus, comprising: meansfor receiving input image data from an input device and for outputtingdecision data based at least in part on count data or data accessvolume, or combinations thereof; and means for receiving the decisiondata and for adjusting scanning speed according to the decision data,wherein said means for receiving the decision data and for adjustingscanning speed is coupled to said means for outputting decision data.22. The apparatus of claim 21, further comprising: means for countingdata access volume inside an image buffer and outputting count data,wherein said means for counting data access volume inside an imagebuffer and outputting count data is coupled to an input terminal of theimage buffer and an output terminal of the image buffer.
 23. Theapparatus of claim 21, further comprising: means for updating said countdata if transfer of input image data into an image buffer is detected;and means for updating said count data if transfer of output image datato the input/output interface is detected.
 24. A method, comprising:providing count data; providing a largest data access volume; anddetermining the scanning speed of a scanner according to a ratio betweenthe count data and the largest data access volume, wherein the scannerscans at less than full speed if the count data is smaller thanapproximately ¾ of the largest data access volume.
 25. The method ofclaim 24, wherein the scanner scans at a speed comprising one or more ofthe following: approximately full speed if the count data is greaterthan approximately ¾ of the largest data access volume, approximately ¾of full speed if the count data is smaller than approximately ¾ of thelargest data access volume but greater than approximately ½ of thelargest data access volume, approximately ½ of full speed if the countdata is smaller than approximately ¾ of the largest data access volumebut greater than approximately ¼ of the largest data access volume,and/or approximately ¼ of full speed if the count data is smaller thanapproximately ¼ of the largest data access volume, or combinationsthereof.
 26. The method of claim 24, further comprising: updating saidcount data if transfer of input image data into an image buffer isdetected or updating said count data if transfer of output image data tothe input/output interface is detected, or combinations thereof.
 27. Anapparatus, comprising: means for providing count data; means forproviding a largest data access volume; and means for determining thescanning speed of a scanner according to a ratio between the count dataand the largest data access volume, wherein the scanning speed is atless than full speed if the count data is smaller than approximately ¾of the largest data access volume.
 28. The apparatus of claim 27,wherein the scanning speed comprises one or more of the following:approximately full speed if the count data is greater than approximately¾ of the largest data access volume, approximately ¾ of full speed ifthe count data is smaller than approximately ¾ of the largest dataaccess volume but greater than approximately ½ of the largest dataaccess volume, approximately ½ of full speed if the count data issmaller than approximately ¾ of the largest data access volume butgreater than approximately ¼ of the largest data access volume, and/orapproximately ¼ of full speed if the count data is smaller thanapproximately ¼ of the largest data access volume, or combinationsthereof.
 28. The apparatus of claim 27, further comprising: means forupdating said count data if transfer of input image data into an imagebuffer is detected; or means for updating said count data if transfer ofoutput image data to the input/output interface is detected, orcombinations thereof.